/*
 * Copyright (c) 2007-2008, Sun Microsystems, Inc.
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in
 *       the documentation and/or other materials provided with the
 *       distribution.
 *     * Neither the name of Sun Microsystems, Inc. nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package com.sun.sgs.io;

import java.io.IOException;

/**
 * Passively initiates connections by listening on a {@link ServerEndpoint} and
 * asynchronously notifies an associated {@link AcceptorListener} of each
 * accepted connection.
 * <p>
 * Once an {@code Acceptor} is listening, it will continue to accept incoming
 * connections until its {@link #shutdown} method is called. An {@code Acceptor}
 * may not be reused once it has started listening or been shut down.
 * 
 * @param <T>
 *           the address family encapsulated by this {@code Acceptor}'s
 *           associated {@link ServerEndpoint}
 */
public interface Acceptor<T> {

   /**
    * Passively accepts incoming connections on the associated
    * {@link ServerEndpoint}. This call may block until listening succeeds, but
    * does not block to wait for incoming connections. Each accepted connection
    * will result in an asynchronous call to
    * {@link AcceptorListener#newConnection newConnection} on the given
    * {@code listener}.
    * 
    * @param listener
    *           the listener that will be notified of new connections
    * 
    * @throws IOException
    *            if there was a problem listening on the {@code ServerEndpoint}
    * @throws IllegalStateException
    *            if the {@code Acceptor} has been shut down or is already
    *            listening
    */
   void listen(AcceptorListener listener) throws IOException;

   /**
    * Returns the {@link ServerEndpoint} this {@code Acceptor} was created with.
    * 
    * @return the {@link ServerEndpoint} this {@code Acceptor} was created with
    */
   ServerEndpoint<T> getEndpoint();

   /**
    * Returns the {@link ServerEndpoint} on which this {@code Acceptor} is
    * listening.
    * 
    * @return the {@link ServerEndpoint} on which this {@code Acceptor} is
    *         listening
    * 
    * @throws IllegalStateException
    *            if the {@code Acceptor} has been shut down or was not listening
    */
   ServerEndpoint<T> getBoundEndpoint();

   /**
    * Shuts down this {@code Acceptor}, releasing any resources in use. Once
    * shutdown, an {@code Acceptor} cannot be restarted.
    * 
    * @throws IllegalStateException
    *            if the {@code Acceptor} has been shut down or was not listening
    */
   void shutdown();

}
